Semiconductors of the III-N type, that is, having the general formula AlxGayIn1-x-yN where 0≦x≦1, 0≦y≦1 and x+y≦1, and, in particular, GaN, have features that make them highly attractive for the optoelectronic, power and radiofrequency applications. However, the development of these applications is hampered by technico-economic limits of AlxGayIn1-x-yN substrates, which are not readily available.
III-N devices are, therefore, commonly fabricated on a substrate formed by the transfer to a support substrate of a thin film taken from a donor substrate of high-grade III-N material suitable for the intended application. The poor availability of AlxGayIn1-x-yN substrates is thus offset by the possibility of using a donor substrate repeatedly.
The SMARTCUT® process is a well-known transfer technique, whereby, in general, a dose of atomic or ionic species is implanted in a donor substrate in order to create an embrittlement area therein at a predefined depth that bounds a thin surface film to be transferred. Then, the donor substrate is bonded to a support substrate, or recipient substrate, and is fractured at the embrittlement area, thereby allowing detachment of the thin surface film now bonded to the recipient substrate.
However, because fracturing substrates made from III-N material requires doses of atomic or ionic species, which are five to ten times higher than in silicon, such processes typically have substantially higher costs than similar processes in silicon.
It can be appreciated, therefore, that it would be advantageous to develop methods for detaching thin films from substrates made from III-N material that overcome these limitations of available processes, for example, being less costly.